NiFeCr layered double hydroxides (NiFeCr-LDHs) supported on graphitic carbon nitride (g-C3N4) hybrids (NiFeCr-LDHs/g-C3N4) are synthesized and used as an electrocatalyst for oxygen evolution reaction (OER) in alkaline media. Effect of g-C3N4 on the structure and OER performance of NiFeCr-LDHs are investigated in detail. g-C3N4 can promote the formation of thin NiFeCr-LDHs nanosheets, thereby enhancing both the number of active sites and OER activity. X-ray photoelectron spectra measurements confirm the electronic interaction between g-C3N4 and NiFeCr-LDHs nanosheets. The OER performance of NiFeCr-LDHs/g-C3N4 hybrids highly relates to the weight ratio of g-C3N4 to NiFeCr-LDHs. When the weight ratio of g-C3N4 to NiFeCr-LDHs is 5%, the corresponding electrocatalyst shows the best OER activity. The component optimized NiFeCr-LDHs/g-C3N4 hybrids display the overpotential of ∼223 mV at 10 mA cm-2 and Tafel slope of 89 mV dec-1 for OER in 1 M KOH solution, which is better than that of pristine NiFeCr-LDHs, bare g-C3N4, and commercial RuO2.